i get hated sometimes because i take ignite on ziggs or someone who normally wouldnt but i do it because our top takes tp bot has heal/exhaust and jungle has smite....am i wrong? i never see a team where its not useful if anything i can ignite the adc (if i can get to them) (also if someone on my team has ignite i dont take it always i just think at least one person should have it)
First of all you're the one playing and if you consider 
on 
do it.
You don't need ignite. There are other ways of providing a healing debuff, some even being inherent to a champion's kit.
Imo a team should have a mix of summoner spells. At least one ignite, heal and exhaust. If you've a jungle, they should have smite. And many top lanes take teleport these days, it allows for your team to respond to a number of situations.
Enemy team have Tryndamere or a fed ADC, ignite them when the fight begins (Or when Tryn ults), they won't be able to lifesteal through everything and Tryn will be dead as soon as his ult ends. Enemy Assassin gets fed, exhaust them, you now have a window of opportunity to either kill them or their team before they can respond. Getting poked down and see a fight about to start, heal!
Its up to you. If you're playing Ziggs, mid I'm assuming, that's basically the only place an ignite can go. The only other champion who should have a free slot is support, but in most cases they should be taking exhaust. It's your choice, take w/e summoners you want. If people hate, let them.
In terms of strategy, though, depending on the enemy teams champions, it may be better to not take it. Also on Ziggs, I personally wouldn't really like it on him as he is a long range poke champion, so you won't really be igniting anyone unless they are jumping on you, and in those cases you most likely will already be dead. On Ziggs I'd rather have Exhaust, or Heal, or maybe even Ghost just for more mobility. Also depending on you are against an assassin like Fizz or Zed, Exhaust is better imo. If anything, just be more flexible with your SS as if you ALWAYS take ignite, you might end up with something that you never can use (if you are losing or never in range to ignite).
yes, you are wrong. you dont need ignite on every team. that being said, if you wanna run it, nobody should give 2 shits about it.
Nothing in this game is ever 100% needed every game (other than good player skill of course) but if you find Ignite useful, go for it. People rage when I don't take Exhaust on Zyra, Morgana, Lulu, or Braum, I just laugh. They have CC. Why would I waste a summoner spell on Exhaust when it's in the kit? I usually don't take Flash on my junglers. I usually do very well anyway. Summoner spells are whatever unless you guys need a specific strategy. Do what you feel contributes to your team the best. Nothing is ever 100% though, so don't fall into that trap.
